Sheshera S Mysore

Overview

The objective of this project was to build a dual channel EEG acquisition device and send the data over to a computer for further analysis. The EEG acquisition device is based on a design by the OpenEEG project.

The hardware makes use of the INA114P instrumentation amplifier and a TLC272 dual op amp for the various filtering and amplification tasks. The Atmega8 AVR Mircocontroller is used for digitization of the signal and transmitted serially to a laptop computer. The laptop lacked a legacy 9-pin serial port, to get around this a Serial to USB converter was used. Our implementation is that of a dual channel of EEG i.e. a EEG may be measured from a twp point on the scalp. But the design of the hardware allows for up to six channels of EEG being measured and transmitted simultaneously.

Implementation

Despite having based the project on the design used by the OpenEEG project I had to make significant changes to their design due to unavailability of components and an inability to make multilayered PCBs as done in the OpenEEG projects. The tasks involved in the project therefore were:

1. A design of the power supply circuit.
2. A complete overhaul of the PCB layout used by the OpenEEG project and a design the PCB layouts.
3. Fabrication of the PCBs, an assembly of the circuit and the enclosures.
4. Writing the firmware of the microcontroller.
5. The signals on the computer were digitally filtered and viewed in a visual programming environment known as BioERA.

Results

On conclusion I was able to observe alpha waves on the on-screen oscilloscope. The project placed second among 70 other projects in the college.

Something that helped me greatly in this project was a month spent at a large city hospital as a in-plant trainee in the biomedical engineering department. (In-plant trainee experience)